[net-next-2.6.git] / fs / gfs2 / meta_io.c

/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/swap.h>
#include <linux/delay.h>
#include <linux/bio.h>
#include <linux/gfs2_ondisk.h>

#include "gfs2.h"
#include "incore.h"
#include "glock.h"
#include "glops.h"
#include "inode.h"
#include "log.h"
#include "lops.h"
#include "meta_io.h"
#include "rgrp.h"
#include "trans.h"
#include "util.h"

static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wbc)
{
	int err;
	struct buffer_head *bh, *head;
	int nr_underway = 0;
	int write_op = (1 << BIO_RW_META) | ((wbc->sync_mode == WB_SYNC_ALL ?
			WRITE_SYNC_PLUG : WRITE));

	BUG_ON(!PageLocked(page));
	BUG_ON(!page_has_buffers(page));

	head = page_buffers(page);
	bh = head;

	do {
		if (!buffer_mapped(bh))
			continue;
		/*
		 * If it's a fully non-blocking write attempt and we cannot
		 * lock the buffer then redirty the page.  Note that this can
		 * potentially cause a busy-wait loop from pdflush and kswapd
		 * activity, but those code paths have their own higher-level
		 * throttling.
		 */
		if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
			lock_buffer(bh);
		} else if (!trylock_buffer(bh)) {
			redirty_page_for_writepage(wbc, page);
			continue;
		}
		if (test_clear_buffer_dirty(bh)) {
			mark_buffer_async_write(bh);
		} else {
			unlock_buffer(bh);
		}
	} while ((bh = bh->b_this_page) != head);

	/*
	 * The page and its buffers are protected by PageWriteback(), so we can
	 * drop the bh refcounts early.
	 */
	BUG_ON(PageWriteback(page));
	set_page_writeback(page);

	do {
		struct buffer_head *next = bh->b_this_page;
		if (buffer_async_write(bh)) {
			submit_bh(write_op, bh);
			nr_underway++;
		}
		bh = next;
	} while (bh != head);
	unlock_page(page);

	err = 0;
	if (nr_underway == 0)
		end_page_writeback(page);

	return err;
}

static const struct address_space_operations aspace_aops = {
	.writepage = gfs2_aspace_writepage,
	.releasepage = gfs2_releasepage,
	.sync_page = block_sync_page,
};

/**
 * gfs2_aspace_get - Create and initialize a struct inode structure
 * @sdp: the filesystem the aspace is in
 *
 * Right now a struct inode is just a struct inode.  Maybe Linux
 * will supply a more lightweight address space construct (that works)
 * in the future.
 *
 * Make sure pages/buffers in this aspace aren't in high memory.
 *
 * Returns: the aspace
 */

struct inode *gfs2_aspace_get(struct gfs2_sbd *sdp)
{
	struct inode *aspace;
	struct gfs2_inode *ip;

	aspace = new_inode(sdp->sd_vfs);
	if (aspace) {
		mapping_set_gfp_mask(aspace->i_mapping, GFP_NOFS);
		aspace->i_mapping->a_ops = &aspace_aops;
		aspace->i_size = ~0ULL;
		ip = GFS2_I(aspace);
		clear_bit(GIF_USER, &ip->i_flags);
		insert_inode_hash(aspace);
	}
	return aspace;
}

void gfs2_aspace_put(struct inode *aspace)
{
	remove_inode_hash(aspace);
	iput(aspace);
}

/**
 * gfs2_meta_sync - Sync all buffers associated with a glock
 * @gl: The glock
 *
 */

void gfs2_meta_sync(struct gfs2_glock *gl)
{
	struct address_space *mapping = gl->gl_aspace->i_mapping;
	int error;

	filemap_fdatawrite(mapping);
	error = filemap_fdatawait(mapping);

	if (error)
		gfs2_io_error(gl->gl_sbd);
}

/**
 * gfs2_getbuf - Get a buffer with a given address space
 * @gl: the glock
 * @blkno: the block number (filesystem scope)
 * @create: 1 if the buffer should be created
 *
 * Returns: the buffer
 */

struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
{
	struct address_space *mapping = gl->gl_aspace->i_mapping;
	struct gfs2_sbd *sdp = gl->gl_sbd;
	struct page *page;
	struct buffer_head *bh;
	unsigned int shift;
	unsigned long index;
	unsigned int bufnum;

	shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
	index = blkno >> shift;             /* convert block to page */
	bufnum = blkno - (index << shift);  /* block buf index within page */

	if (create) {
		for (;;) {
			page = grab_cache_page(mapping, index);
			if (page)
				break;
			yield();
		}
	} else {
		page = find_lock_page(mapping, index);
		if (!page)
			return NULL;
	}

	if (!page_has_buffers(page))
		create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);

	/* Locate header for our buffer within our page */
	for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
		/* Do nothing */;
	get_bh(bh);

	if (!buffer_mapped(bh))
		map_bh(bh, sdp->sd_vfs, blkno);

	unlock_page(page);
	mark_page_accessed(page);
	page_cache_release(page);

	return bh;
}

static void meta_prep_new(struct buffer_head *bh)
{
	struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;

	lock_buffer(bh);
	clear_buffer_dirty(bh);
	set_buffer_uptodate(bh);
	unlock_buffer(bh);

	mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
}

/**
 * gfs2_meta_new - Get a block
 * @gl: The glock associated with this block
 * @blkno: The block number
 *
 * Returns: The buffer
 */

struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
{
	struct buffer_head *bh;
	bh = gfs2_getbuf(gl, blkno, CREATE);
	meta_prep_new(bh);
	return bh;
}

/**
 * gfs2_meta_read - Read a block from disk
 * @gl: The glock covering the block
 * @blkno: The block number
 * @flags: flags
 * @bhp: the place where the buffer is returned (NULL on failure)
 *
 * Returns: errno
 */

int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
		   struct buffer_head **bhp)
{
	struct gfs2_sbd *sdp = gl->gl_sbd;
	struct buffer_head *bh;

	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
		return -EIO;

	*bhp = bh = gfs2_getbuf(gl, blkno, CREATE);

	lock_buffer(bh);
	if (buffer_uptodate(bh)) {
		unlock_buffer(bh);
		return 0;
	}
	bh->b_end_io = end_buffer_read_sync;
	get_bh(bh);
	submit_bh(READ_SYNC | (1 << BIO_RW_META), bh);
	if (!(flags & DIO_WAIT))
		return 0;

	wait_on_buffer(bh);
	if (unlikely(!buffer_uptodate(bh))) {
		struct gfs2_trans *tr = current->journal_info;
		if (tr && tr->tr_touched)
			gfs2_io_error_bh(sdp, bh);
		brelse(bh);
		return -EIO;
	}

	return 0;
}

/**
 * gfs2_meta_wait - Reread a block from disk
 * @sdp: the filesystem
 * @bh: The block to wait for
 *
 * Returns: errno
 */

int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
{
	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
		return -EIO;

	wait_on_buffer(bh);

	if (!buffer_uptodate(bh)) {
		struct gfs2_trans *tr = current->journal_info;
		if (tr && tr->tr_touched)
			gfs2_io_error_bh(sdp, bh);
		return -EIO;
	}
	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
		return -EIO;

	return 0;
}

/**
 * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
 * @gl: the glock the buffer belongs to
 * @bh: The buffer to be attached to
 * @meta: Flag to indicate whether its metadata or not
 */

void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
			 int meta)
{
	struct gfs2_bufdata *bd;

	if (meta)
		lock_page(bh->b_page);

	if (bh->b_private) {
		if (meta)
			unlock_page(bh->b_page);
		return;
	}

	bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
	bd->bd_bh = bh;
	bd->bd_gl = gl;

	INIT_LIST_HEAD(&bd->bd_list_tr);
	if (meta)
		lops_init_le(&bd->bd_le, &gfs2_buf_lops);
	else
		lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
	bh->b_private = bd;

	if (meta)
		unlock_page(bh->b_page);
}

void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta)
{
	struct gfs2_sbd *sdp = GFS2_SB(bh->b_page->mapping->host);
	struct gfs2_bufdata *bd = bh->b_private;
	if (test_clear_buffer_pinned(bh)) {
		list_del_init(&bd->bd_le.le_list);
		if (meta) {
			gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
			sdp->sd_log_num_buf--;
			tr->tr_num_buf_rm++;
		} else {
			gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
			sdp->sd_log_num_databuf--;
			tr->tr_num_databuf_rm++;
		}
		tr->tr_touched = 1;
		brelse(bh);
	}
	if (bd) {
		if (bd->bd_ail) {
			gfs2_remove_from_ail(bd);
			bh->b_private = NULL;
			bd->bd_bh = NULL;
			bd->bd_blkno = bh->b_blocknr;
			gfs2_trans_add_revoke(sdp, bd);
		}
	}
	clear_buffer_dirty(bh);
	clear_buffer_uptodate(bh);
}

/**
 * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 * @ip: the inode who owns the buffers
 * @bstart: the first buffer in the run
 * @blen: the number of buffers in the run
 *
 */

void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
{
	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
	struct buffer_head *bh;

	while (blen) {
		bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
		if (bh) {
			lock_buffer(bh);
			gfs2_log_lock(sdp);
			gfs2_remove_from_journal(bh, current->journal_info, 1);
			gfs2_log_unlock(sdp);
			unlock_buffer(bh);
			brelse(bh);
		}

		bstart++;
		blen--;
	}
}

/**
 * gfs2_meta_indirect_buffer - Get a metadata buffer
 * @ip: The GFS2 inode
 * @height: The level of this buf in the metadata (indir addr) tree (if any)
 * @num: The block number (device relative) of the buffer
 * @new: Non-zero if we may create a new buffer
 * @bhp: the buffer is returned here
 *
 * Returns: errno
 */

int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
			      int new, struct buffer_head **bhp)
{
	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
	struct gfs2_glock *gl = ip->i_gl;
	struct buffer_head *bh;
	int ret = 0;

	if (new) {
		BUG_ON(height == 0);
		bh = gfs2_meta_new(gl, num);
		gfs2_trans_add_bh(ip->i_gl, bh, 1);
		gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
		gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
	} else {
		u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
		ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
		if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
			brelse(bh);
			ret = -EIO;
		}
	}
	*bhp = bh;
	return ret;
}

/**
 * gfs2_meta_ra - start readahead on an extent of a file
 * @gl: the glock the blocks belong to
 * @dblock: the starting disk block
 * @extlen: the number of blocks in the extent
 *
 * returns: the first buffer in the extent
 */

struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
{
	struct gfs2_sbd *sdp = gl->gl_sbd;
	struct buffer_head *first_bh, *bh;
	u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
			  sdp->sd_sb.sb_bsize_shift;

	BUG_ON(!extlen);

	if (max_ra < 1)
		max_ra = 1;
	if (extlen > max_ra)
		extlen = max_ra;

	first_bh = gfs2_getbuf(gl, dblock, CREATE);

	if (buffer_uptodate(first_bh))
		goto out;
	if (!buffer_locked(first_bh))
		ll_rw_block(READ_SYNC | (1 << BIO_RW_META), 1, &first_bh);

	dblock++;
	extlen--;

	while (extlen) {
		bh = gfs2_getbuf(gl, dblock, CREATE);

		if (!buffer_uptodate(bh) && !buffer_locked(bh))
			ll_rw_block(READA, 1, &bh);
		brelse(bh);
		dblock++;
		extlen--;
		if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
			goto out;
	}

	wait_on_buffer(first_bh);
out:
	return first_bh;
}
Commit	Line	Data
b3b94faa DT	1	/*
b3b94faa DT	2	* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
091806ed	3	* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
b3b94faa DT	4	*
	5	* This copyrighted material is made available to anyone wishing to use,
	6	* modify, copy, or redistribute it subject to the terms and conditions
e9fc2aa0	7	* of the GNU General Public License version 2.
b3b94faa DT	8	*/
	9
	10	#include <linux/sched.h>
	11	#include <linux/slab.h>
	12	#include <linux/spinlock.h>
	13	#include <linux/completion.h>
	14	#include <linux/buffer_head.h>
	15	#include <linux/mm.h>
	16	#include <linux/pagemap.h>
	17	#include <linux/writeback.h>
	18	#include <linux/swap.h>
	19	#include <linux/delay.h>
2e565bb6	20	#include <linux/bio.h>
5c676f6d	21	#include <linux/gfs2_ondisk.h>
b3b94faa DT	22
b3b94faa DT	23	#include "gfs2.h"
5c676f6d	24	#include "incore.h"
b3b94faa DT	25	#include "glock.h"
	26	#include "glops.h"
	27	#include "inode.h"
	28	#include "log.h"
	29	#include "lops.h"
	30	#include "meta_io.h"
	31	#include "rgrp.h"
	32	#include "trans.h"
5c676f6d	33	#include "util.h"
b3b94faa	34
4a0f9a32	35	static int gfs2_aspace_writepage(struct page page, struct writeback_control wbc)
b3b94faa	36	{
4a0f9a32 SW	37	int err;
	38	struct buffer_head bh, head;
	39	int nr_underway = 0;
	40	int write_op = (1 << BIO_RW_META) \| ((wbc->sync_mode == WB_SYNC_ALL ?
	41	WRITE_SYNC_PLUG : WRITE));
b3b94faa	42
4a0f9a32 SW	43	BUG_ON(!PageLocked(page));
	44	BUG_ON(!page_has_buffers(page));
	45
	46	head = page_buffers(page);
	47	bh = head;
	48
	49	do {
	50	if (!buffer_mapped(bh))
	51	continue;
	52	/*
	53	* If it's a fully non-blocking write attempt and we cannot
	54	* lock the buffer then redirty the page. Note that this can
	55	* potentially cause a busy-wait loop from pdflush and kswapd
	56	* activity, but those code paths have their own higher-level
	57	* throttling.
	58	*/
	59	if (wbc->sync_mode != WB_SYNC_NONE \|\| !wbc->nonblocking) {
	60	lock_buffer(bh);
	61	} else if (!trylock_buffer(bh)) {
	62	redirty_page_for_writepage(wbc, page);
	63	continue;
	64	}
	65	if (test_clear_buffer_dirty(bh)) {
	66	mark_buffer_async_write(bh);
	67	} else {
	68	unlock_buffer(bh);
	69	}
	70	} while ((bh = bh->b_this_page) != head);
	71
	72	/*
	73	* The page and its buffers are protected by PageWriteback(), so we can
	74	* drop the bh refcounts early.
	75	*/
	76	BUG_ON(PageWriteback(page));
	77	set_page_writeback(page);
	78
	79	do {
	80	struct buffer_head *next = bh->b_this_page;
	81	if (buffer_async_write(bh)) {
	82	submit_bh(write_op, bh);
	83	nr_underway++;
	84	}
	85	bh = next;
	86	} while (bh != head);
	87	unlock_page(page);
	88
	89	err = 0;
	90	if (nr_underway == 0)
	91	end_page_writeback(page);
	92
	93	return err;
b3b94faa DT	94	}
b3b94faa DT	95
66de045d	96	static const struct address_space_operations aspace_aops = {
b3b94faa	97	.writepage = gfs2_aspace_writepage,
4340fe62	98	.releasepage = gfs2_releasepage,
52d4c74b	99	.sync_page = block_sync_page,
b3b94faa DT	100	};
	101
	102	/**
	103	* gfs2_aspace_get - Create and initialize a struct inode structure
	104	* @sdp: the filesystem the aspace is in
	105	*
	106	* Right now a struct inode is just a struct inode. Maybe Linux
	107	* will supply a more lightweight address space construct (that works)
	108	* in the future.
	109	*
	110	* Make sure pages/buffers in this aspace aren't in high memory.
	111	*
	112	* Returns: the aspace
	113	*/
	114
	115	struct inode gfs2_aspace_get(struct gfs2_sbd sdp)
	116	{
	117	struct inode *aspace;
091806ed	118	struct gfs2_inode *ip;
b3b94faa DT	119
	120	aspace = new_inode(sdp->sd_vfs);
	121	if (aspace) {
f3bba03f	122	mapping_set_gfp_mask(aspace->i_mapping, GFP_NOFS);
b3b94faa DT	123	aspace->i_mapping->a_ops = &aspace_aops;
b3b94faa DT	124	aspace->i_size = ~0ULL;
091806ed BP	125	ip = GFS2_I(aspace);
091806ed BP	126	clear_bit(GIF_USER, &ip->i_flags);
b3b94faa DT	127	insert_inode_hash(aspace);
b3b94faa DT	128	}
b3b94faa DT	129	return aspace;
	130	}
	131
	132	void gfs2_aspace_put(struct inode *aspace)
	133	{
	134	remove_inode_hash(aspace);
	135	iput(aspace);
	136	}
	137
b3b94faa DT	138	/**
	139	* gfs2_meta_sync - Sync all buffers associated with a glock
	140	* @gl: The glock
b3b94faa DT	141	*
	142	*/
	143
7276b3b0	144	void gfs2_meta_sync(struct gfs2_glock *gl)
b3b94faa DT	145	{
b3b94faa DT	146	struct address_space *mapping = gl->gl_aspace->i_mapping;
7276b3b0	147	int error;
b3b94faa	148
7276b3b0 SW	149	filemap_fdatawrite(mapping);
7276b3b0 SW	150	error = filemap_fdatawait(mapping);
b3b94faa DT	151
	152	if (error)
	153	gfs2_io_error(gl->gl_sbd);
	154	}
	155
	156	/**
6802e340	157	* gfs2_getbuf - Get a buffer with a given address space
cb4c0313	158	* @gl: the glock
b3b94faa DT	159	* @blkno: the block number (filesystem scope)
	160	* @create: 1 if the buffer should be created
	161	*
	162	* Returns: the buffer
	163	*/
	164
6802e340	165	struct buffer_head gfs2_getbuf(struct gfs2_glock gl, u64 blkno, int create)
b3b94faa	166	{
cb4c0313 SW	167	struct address_space *mapping = gl->gl_aspace->i_mapping;
cb4c0313 SW	168	struct gfs2_sbd *sdp = gl->gl_sbd;
b3b94faa DT	169	struct page *page;
	170	struct buffer_head *bh;
	171	unsigned int shift;
	172	unsigned long index;
	173	unsigned int bufnum;
	174
	175	shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
	176	index = blkno >> shift; /* convert block to page */
	177	bufnum = blkno - (index << shift); /* block buf index within page */
	178
	179	if (create) {
	180	for (;;) {
cb4c0313	181	page = grab_cache_page(mapping, index);
b3b94faa DT	182	if (page)
	183	break;
	184	yield();
	185	}
	186	} else {
cb4c0313	187	page = find_lock_page(mapping, index);
b3b94faa DT	188	if (!page)
	189	return NULL;
	190	}
	191
	192	if (!page_has_buffers(page))
	193	create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
	194
	195	/* Locate header for our buffer within our page */
	196	for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
	197	/* Do nothing */;
	198	get_bh(bh);
	199
	200	if (!buffer_mapped(bh))
	201	map_bh(bh, sdp->sd_vfs, blkno);
	202
	203	unlock_page(page);
	204	mark_page_accessed(page);
	205	page_cache_release(page);
	206
	207	return bh;
	208	}
	209
	210	static void meta_prep_new(struct buffer_head *bh)
	211	{
	212	struct gfs2_meta_header mh = (struct gfs2_meta_header )bh->b_data;
	213
	214	lock_buffer(bh);
	215	clear_buffer_dirty(bh);
	216	set_buffer_uptodate(bh);
	217	unlock_buffer(bh);
	218
	219	mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
	220	}
	221
	222	/**
	223	* gfs2_meta_new - Get a block
	224	* @gl: The glock associated with this block
	225	* @blkno: The block number
	226	*
	227	* Returns: The buffer
	228	*/
	229
cd915493	230	struct buffer_head gfs2_meta_new(struct gfs2_glock gl, u64 blkno)
b3b94faa DT	231	{
b3b94faa DT	232	struct buffer_head *bh;
6802e340	233	bh = gfs2_getbuf(gl, blkno, CREATE);
b3b94faa DT	234	meta_prep_new(bh);
	235	return bh;
	236	}
	237
	238	/**
	239	* gfs2_meta_read - Read a block from disk
	240	* @gl: The glock covering the block
	241	* @blkno: The block number
7276b3b0	242	* @flags: flags
b3b94faa DT	243	* @bhp: the place where the buffer is returned (NULL on failure)
	244	*
	245	* Returns: errno
	246	*/
	247
cd915493	248	int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
b3b94faa DT	249	struct buffer_head **bhp)
b3b94faa DT	250	{
c969f58c SW	251	struct gfs2_sbd *sdp = gl->gl_sbd;
	252	struct buffer_head *bh;
	253
	254	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
	255	return -EIO;
	256
	257	*bhp = bh = gfs2_getbuf(gl, blkno, CREATE);
	258
	259	lock_buffer(bh);
	260	if (buffer_uptodate(bh)) {
	261	unlock_buffer(bh);
	262	return 0;
	263	}
	264	bh->b_end_io = end_buffer_read_sync;
	265	get_bh(bh);
	266	submit_bh(READ_SYNC \| (1 << BIO_RW_META), bh);
	267	if (!(flags & DIO_WAIT))
	268	return 0;
	269
	270	wait_on_buffer(bh);
	271	if (unlikely(!buffer_uptodate(bh))) {
	272	struct gfs2_trans *tr = current->journal_info;
	273	if (tr && tr->tr_touched)
	274	gfs2_io_error_bh(sdp, bh);
	275	brelse(bh);
	276	return -EIO;
7276b3b0	277	}
b3b94faa	278
7276b3b0	279	return 0;
b3b94faa DT	280	}
	281
	282	/**
7276b3b0	283	* gfs2_meta_wait - Reread a block from disk
b3b94faa	284	* @sdp: the filesystem
7276b3b0	285	* @bh: The block to wait for
b3b94faa DT	286	*
	287	* Returns: errno
	288	*/
	289
7276b3b0	290	int gfs2_meta_wait(struct gfs2_sbd sdp, struct buffer_head bh)
b3b94faa DT	291	{
	292	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
	293	return -EIO;
	294
7276b3b0	295	wait_on_buffer(bh);
b3b94faa	296
7276b3b0 SW	297	if (!buffer_uptodate(bh)) {
	298	struct gfs2_trans *tr = current->journal_info;
	299	if (tr && tr->tr_touched)
	300	gfs2_io_error_bh(sdp, bh);
	301	return -EIO;
b3b94faa	302	}
7276b3b0 SW	303	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
7276b3b0 SW	304	return -EIO;
b3b94faa DT	305
	306	return 0;
	307	}
	308
	309	/**
586dfdaa	310	* gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
b3b94faa DT	311	* @gl: the glock the buffer belongs to
b3b94faa DT	312	* @bh: The buffer to be attached to
586dfdaa	313	* @meta: Flag to indicate whether its metadata or not
b3b94faa DT	314	*/
b3b94faa DT	315
568f4c96 SW	316	void gfs2_attach_bufdata(struct gfs2_glock gl, struct buffer_head bh,
568f4c96 SW	317	int meta)
b3b94faa DT	318	{
	319	struct gfs2_bufdata *bd;
	320
18ec7d5c SW	321	if (meta)
18ec7d5c SW	322	lock_page(bh->b_page);
b3b94faa	323
5c676f6d	324	if (bh->b_private) {
18ec7d5c SW	325	if (meta)
18ec7d5c SW	326	unlock_page(bh->b_page);
b3b94faa DT	327	return;
	328	}
	329
3e5cd087	330	bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS \| __GFP_NOFAIL);
b3b94faa DT	331	bd->bd_bh = bh;
	332	bd->bd_gl = gl;
	333
	334	INIT_LIST_HEAD(&bd->bd_list_tr);
82ffa516	335	if (meta)
586dfdaa	336	lops_init_le(&bd->bd_le, &gfs2_buf_lops);
82ffa516	337	else
586dfdaa	338	lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
5c676f6d	339	bh->b_private = bd;
b3b94faa	340
18ec7d5c SW	341	if (meta)
18ec7d5c SW	342	unlock_page(bh->b_page);
b3b94faa DT	343	}
b3b94faa DT	344
16615be1 SW	345	void gfs2_remove_from_journal(struct buffer_head bh, struct gfs2_trans tr, int meta)
	346	{
	347	struct gfs2_sbd *sdp = GFS2_SB(bh->b_page->mapping->host);
	348	struct gfs2_bufdata *bd = bh->b_private;
	349	if (test_clear_buffer_pinned(bh)) {
	350	list_del_init(&bd->bd_le.le_list);
	351	if (meta) {
	352	gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
	353	sdp->sd_log_num_buf--;
	354	tr->tr_num_buf_rm++;
	355	} else {
	356	gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
	357	sdp->sd_log_num_databuf--;
	358	tr->tr_num_databuf_rm++;
	359	}
	360	tr->tr_touched = 1;
	361	brelse(bh);
	362	}
	363	if (bd) {
	364	if (bd->bd_ail) {
f91a0d3e	365	gfs2_remove_from_ail(bd);
16615be1 SW	366	bh->b_private = NULL;
	367	bd->bd_bh = NULL;
	368	bd->bd_blkno = bh->b_blocknr;
	369	gfs2_trans_add_revoke(sdp, bd);
	370	}
	371	}
	372	clear_buffer_dirty(bh);
	373	clear_buffer_uptodate(bh);
	374	}
	375
b3b94faa DT	376	/**
	377	* gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
	378	* @ip: the inode who owns the buffers
	379	* @bstart: the first buffer in the run
	380	* @blen: the number of buffers in the run
	381	*
	382	*/
	383
cd915493	384	void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
b3b94faa	385	{
feaa7bba	386	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
b3b94faa DT	387	struct buffer_head *bh;
	388
	389	while (blen) {
6802e340	390	bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
b3b94faa	391	if (bh) {
1ad38c43 SW	392	lock_buffer(bh);
1ad38c43 SW	393	gfs2_log_lock(sdp);
16615be1	394	gfs2_remove_from_journal(bh, current->journal_info, 1);
1ad38c43	395	gfs2_log_unlock(sdp);
b3b94faa	396	unlock_buffer(bh);
b3b94faa DT	397	brelse(bh);
	398	}
	399
	400	bstart++;
	401	blen--;
	402	}
	403	}
	404
b3b94faa DT	405	/**
	406	* gfs2_meta_indirect_buffer - Get a metadata buffer
	407	* @ip: The GFS2 inode
	408	* @height: The level of this buf in the metadata (indir addr) tree (if any)
	409	* @num: The block number (device relative) of the buffer
	410	* @new: Non-zero if we may create a new buffer
	411	* @bhp: the buffer is returned here
	412	*
b3b94faa DT	413	* Returns: errno
	414	*/
	415
cd915493	416	int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
b3b94faa DT	417	int new, struct buffer_head **bhp)
b3b94faa DT	418	{
7276b3b0 SW	419	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
7276b3b0 SW	420	struct gfs2_glock *gl = ip->i_gl;
f91a0d3e SW	421	struct buffer_head *bh;
f91a0d3e SW	422	int ret = 0;
b3b94faa DT	423
b3b94faa DT	424	if (new) {
f91a0d3e SW	425	BUG_ON(height == 0);
f91a0d3e SW	426	bh = gfs2_meta_new(gl, num);
d4e9c4c3	427	gfs2_trans_add_bh(ip->i_gl, bh, 1);
b3b94faa DT	428	gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
b3b94faa DT	429	gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
7276b3b0 SW	430	} else {
7276b3b0 SW	431	u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
f91a0d3e SW	432	ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
	433	if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
	434	brelse(bh);
	435	ret = -EIO;
7276b3b0	436	}
b3b94faa	437	}
b3b94faa	438	*bhp = bh;
f91a0d3e	439	return ret;
b3b94faa DT	440	}
	441
	442	/**
	443	* gfs2_meta_ra - start readahead on an extent of a file
	444	* @gl: the glock the blocks belong to
	445	* @dblock: the starting disk block
	446	* @extlen: the number of blocks in the extent
	447	*
7276b3b0	448	* returns: the first buffer in the extent
b3b94faa DT	449	*/
b3b94faa DT	450
7276b3b0	451	struct buffer_head gfs2_meta_ra(struct gfs2_glock gl, u64 dblock, u32 extlen)
b3b94faa DT	452	{
b3b94faa DT	453	struct gfs2_sbd *sdp = gl->gl_sbd;
b3b94faa	454	struct buffer_head first_bh, bh;
cd915493	455	u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
568f4c96	456	sdp->sd_sb.sb_bsize_shift;
b3b94faa	457
7276b3b0 SW	458	BUG_ON(!extlen);
	459
	460	if (max_ra < 1)
	461	max_ra = 1;
b3b94faa DT	462	if (extlen > max_ra)
	463	extlen = max_ra;
	464
6802e340	465	first_bh = gfs2_getbuf(gl, dblock, CREATE);
b3b94faa DT	466
	467	if (buffer_uptodate(first_bh))
	468	goto out;
7276b3b0	469	if (!buffer_locked(first_bh))
c969f58c	470	ll_rw_block(READ_SYNC \| (1 << BIO_RW_META), 1, &first_bh);
b3b94faa DT	471
	472	dblock++;
	473	extlen--;
	474
	475	while (extlen) {
6802e340	476	bh = gfs2_getbuf(gl, dblock, CREATE);
b3b94faa	477
7276b3b0 SW	478	if (!buffer_uptodate(bh) && !buffer_locked(bh))
	479	ll_rw_block(READA, 1, &bh);
	480	brelse(bh);
b3b94faa DT	481	dblock++;
b3b94faa DT	482	extlen--;
7276b3b0 SW	483	if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
7276b3b0 SW	484	goto out;
b3b94faa DT	485	}
b3b94faa DT	486
7276b3b0	487	wait_on_buffer(first_bh);
a91ea69f	488	out:
7276b3b0	489	return first_bh;
b3b94faa DT	490	}
b3b94faa DT	491